English

Temperature-dependent nuclear partition functions and abundances in stellar interior

Nuclear Theory 2025-05-13 v1

Abstract

We calculate temperature-dependent nuclear partition functions (TDNPFs) and nuclear abundances for 728728 nuclei assuming nuclear statistical equilibrium (NSE). The theories of stellar evolution support NSE. Discrete nuclear energy levels have been calculated \textit{microscopically}, using the pn-QRPA theory, up to an excitation energy of 1010 MeV in the calculation of TDNPFs. This feature of our paper distinguishes it from previous calculations. Experimental data is also incorporated wherever available to ensure reliability of our results. Beyond 10 MeV we employ simple Fermi gas model and perform integration over the nuclear level densities to approximate the TDNPFs. We calculate nuclidic abundances, using the Saha equation, as a function of three parameters: stellar density, stellar temperature and lepton-to-baryon content of stellar matter. All these physical parameters are considered to be extremely important in stellar interior. Results obtained in this paper show that the equilibrium configuration of nuclei remains unaltered by increasing stellar density (only calculated nuclear abundances increases by roughly same order of magnitude). Increasing the stellar temperature smooths the equilibrium configuration showing peaks at neutron-number magic nuclei.

Keywords

Cite

@article{arxiv.2505.06674,
  title  = {Temperature-dependent nuclear partition functions and abundances in stellar interior},
  author = {Jameel-Un Nabi and Abdel Nasser Tawfik and Nada Ezzelarab and Ali Abas Khan},
  journal= {arXiv preprint arXiv:2505.06674},
  year   = {2025}
}

Comments

42 Page, 21 Table, 8 Figures

R2 v1 2026-06-28T23:28:11.457Z